| LINER GUARDIAN - LINER CONDITION MONITORING SYSTEM |  download PDFEuropean Patent Nº 2227670 – Certificate
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Liner scuffing is one of the most common failures in our day’s engines. The mechanisms of liner scuffing have been investigated for some years and no absolute conclusions have been made until now. TecnoVeritas decided to produce research in this area of Diesel engines tribology, developing a test rig and finally the commercial system.
Liner Guardian, as the name indicates, is a protection system that can be installed in existing engines, monitoring the condition of the working surfaces of the pistons, through the continuous monitoring of the roughness, pressure and temperature.
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Example of scuffed engine cylinder parts. |
Each time the pistons go up and down, a number of high resolution non-contact roughness sensors read the surface roughness and compares it with original or reference roughness profile.
In case a pre-defined roughness deviation is reached, an alarm is raised, allowing that actions can be taken to alleviate the developing damage by engine load reduction and correction of lub oil feed rates, or immediate maintenance.
The system is also capable of measuring the piston rings condition, as well as the oil film thickness, therefore giving valuable information to the engineers.
Liner Guardian is composed by a number of sensors radially disposed around the cylinder liner (typically four diametrically opposed), and a box containing the computing unit.
All the cylinders boxes are interconnected through a CANbus network, sending the cycle by cycle information to a computer unit, for analysis and data management.
Comprehensive monitoring software was also installed, allowing the data retrieving of each cylinder, for further analysis.
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Right hand side figure: we can see some scuffed material on the piston surface (black part above the piston rings). Left hand side figure: cleaned piston rings viewed from the cylinder liner ports. |
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Scuffed piston rings surfaces. |
Due to the need of investigating which are the variables that determine the cylinders components scuffing process, on big crosshead diesel engines, TecnoVeritas developed a test rig that allowed recreating the functioning condition of the cylinder, concerning the interaction between the piston rings and the liner.
The developed mechanism allow the simulation of the cylinder’s components operation, such as: contact charge between piston rings and liner, piston rings’ linear speed relatively to the liner, piston rings-liner contact surfaces temperature and lubrication rate, measuring simultaneously instantaneous absolute roughness, using a very high resolution roughness sensor, transported on the piston ring support.
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This experimental mechanism was used as scientific base to develop Liner Guardian System valid for protection against scuffing phenomena, on marine engines and low speed stationary engines liners.
Liner Guardian is actually being offered to the market.
